my $sth = $dbh->prepare_cached("SELECT foo,bar from table where id = ?");
for my $id (@ids) {
    $sth->execute( $id );
    my @results = $sth->fetchrow_array;
    $sth->finish;
}

##</code><code>##

my $placeholders = join ',', ('?') x @ids;
my $sth = $dbh->prepare_cached(
    "SELECT id,foo,bar from table where id IN ($placeholders)",
);

$sth->execute( @ids );
$sth->bind_columns( \my ($id, $foo, $bar ) );

while ( $sth->fetch ) {
    # Put values somewhere
}
$sth->finish;